This invention is in the field of sewing machines; more particularly, it is concerned with a device to change the phase relationship between a feed cam or cams and the lateral needle deflection cam or cams of a sewing machine.
In sewing machines having ornamental pattern capability, it is generally provided that needle deflection cams are used in conjunction with feed cams in order to provide ornamental patterns necessitating backward and forward motion of the work material in addition to the deflection of the sewing needle. It has been observed that with certain utilitarian needle deflection cams such as blind stitch or multistitch, a feed cam may be utilized which will provide for other utilitarian or ornamental stitches by utilizing the variable feed thus provided. It is further known in the sewing machine art that additional utilitarian and ornamental patterns can be obtained by rephasing the feed cam, that is, by altering the angular relationship between the feed cams and the needle position cams. Such an arrangement is shown in U.S. Pat. No. 2,999,471 issued on Sept. 12, 1961, to Benick et al. In the above noted patent, there are disclosed two feed cams which may be rotated to any one of twelve positions with respect to the needle position cams and any one of two different heights to permit utilization of a selected one of the feed cams. Such a device presents a degree of complexity to an operator which may inhibit the use of such a device.
What is required is a simple device which may be readily comprehended by an operator in order to obtain patterns having a high degree of ornamental and utilitarian use.